There is decentralised finance (defi). One example of application is lending your money (in stablecoin or token format) in a lending protocol of your choice. You can expect a very good yield compared to traditional finance. Aave and Compound are the most famous. This is one type of the many financial applications developed on Ethereum's smart contracts.
Indeed I think they don't ship the whole browser package.
What they might actually do is to locally launch a HTTP server which renders the app if you call it on any browser (localhost:8080 in the examples). The chrome of the app is actually a thin layer that use the default OS web browser. That is why the memory footprint is much less higher that alternatives like electron.
What a surprise: developers getting screwed by big centralized companies. Nowadays wasting time and money building anything on the shoulder of another company is crazy. It's not if but when are you getting screwed: Twitter, Facebook, Apple, this is history repeating itself plenty fold.
I'm just surprised nobody mentioned any decentralised, blockchain-based platform where spending time and money building on it is just worth it for the future.
Have a look at the Steem blockchain: social network like publishing and commenting are free and even rewarded with crypto-currency payouts. And as a developer it is very elegant to develop on it.